If you've managed to avoid spoilers, then don't read this post over at Blizzard's official site, because it goes into great detail on what the big patch 5.4 raid is all about, complete with commentary with Lead Encounter Designer Ion "Watcher" Hazzikostas. If, however, you're like me and you just can't get enough detail on this kind of thing, then here are a few details from the long overview I found particularly interesting. Each and every one of them is a spoiler, so be warned.

The first encounter, Immerseus, is one that us old players "may find the fight structure somewhat reminiscent of Viscidus in the Temple of Ahn'Qiraj."

The Galakras encounter is rooted in the lore of the Twilight Highlands quests Horde side, and also has that storming the beaches feel to it, with multiple waves of enemies to deal with before the boss himself.

When talking about the Dark Shaman encounter, Ion says "The attire for these two wolfriders was inspired by the traditional Warcraft III Shaman unit, and we're excited to be able to give lucky Shaman players a chance to earn that look for themselves by defeating this encounter." He's specifically talking about these.

The Spoils of Pandaria encounter isn't a fight with a traditional 'boss' as such, but rather your raid trying to shut down a 'security system' before it overwhelms you.

The Garrosh Hellscream encounter is definitely going to hearken back to Pandaria itself - "As Garrosh wields the power of Y'Shaarj-origin of all the sha-players must battle through some of the most memorable locations where the sha manifested in Pandaria"

There's a lot of detail to sift through, so again, if you're the curious type definitely take a look at the post. I'll be scouring it over and over again over the next few days.